Check end clearance of piston rings

Prerequisite 

Cylinder path is cleaned.

Cylinder was measured and is within the permissible tolerances.

Check 

• Connect the upper piston ring to the cylinder and push it with the piston to the upper dead center.
• Check the end clearance of the upper piston ring with a feeler gauge.

Courtesy of BMW OF NORTH AMERICA, INC.

End clearance of upper piston ring
Before measuring the end clearance, make sure the cylinder is within the permissible tolerance.	0.20 mm... 0.28 mm

Result 

» End clearance is outside tolerance.

Measure 

• Replace upper piston ring.

Check 

• Take upper piston ring out of the cylinder.
• Connect the central piston ring to the cylinder and push it with the piston to the upper dead center.
• Check the end clearance of the center piston ring with a feeler gauge.

Courtesy of BMW OF NORTH AMERICA, INC.

End clearance of center piston ring
Before measuring the end clearance, make sure the cylinder is within the permissible tolerance.	0.20 mm... 0.28 mm

Result 

» End clearance is outside tolerance.

Measure 

• Replace center piston ring.